1. Field of the Invention
This invention relates to jet powered watercraft, especially personal watercraft (“PWC”). In particular, the invention is directed to a towing apparatus for a PWC.
2. Description of Related Art
Conventional pulling apparatus on watercraft consists of tow eye hooks extending from the deck or hull or pylons that extend upwardly from the deck. Typical pylons are rigid poles, some of which extend by telescoping. Pylons are often supported by guy lines or poles from the deck so that the upstanding pylon does not pull out of its mooring during use. Pylons can be single poles or can be formed as towers or roll cages.
FIGS. 7 and 8 illustrate examples of these prior art pulling apparatuses. Each figure shows the rear of a watercraft 310 having a hull 312 and a deck 314. A steering nozzle 316 extends from the jet propulsion system as is conventionally known through the rear of the hull 312. A pedestal 318 extends from the deck 314 and supports a seat 320 and a grab handle 322. Behind the seat 320 and pedestal 318 is a reboarding platform 324 formed in the deck 314, which provides a space onto which a person in the water may climb onto the watercraft 310. As shown in FIG. 7, one apparatus for attaching a tow line to a watercraft 310 is a tow eye hook 326. And as shown in FIG. 8, another apparatus is a telescoping pylon 328, having a spool 330 at the top and a joint 332 for collapsing the telescoping pylon 328 near the middle of the pylon.
When pulling or towing an object with a watercraft, the watercraft can experience a force from the object that causes the watercraft to move. There are three different types of movements typically experienced by a watercraft: yaw, roll, and pitch. Yaw describes movement about a vertical axis. Roll means to move from side to side about a longitudinal axis. Pitch describes movement about a lateral axis, as in the bow slanting up or down. For example, a sport boat pulling a water skier can be pulled from side to side when the skier traverses the wake. This lateral movement of the stem of the watercraft, or yaw, can affect the ride of the watercraft.
When a pylon is used to pull an object, the force exerted by the object also affects the watercraft along its longitudinal axis as the force is applied above the hull of the watercraft. So, if a wake boarder, for example, makes a hard side cut, the watercraft can experience a lateral force applied at the top of the pylon where the tow rope is secured. This can cause the watercraft to roll to one side, again affecting the ride.
An object being pulled by a watercraft can also create a downward movement of the stem relative to the bow of the watercraft. This movement, or pitch, can be amplified by the application of the pulling force at the top of the pylon.
The effect of a towed object is more pronounced in lighter watercraft, such as personal watercraft (PWC). In that case, a wake boarder, for example, can exert a large pulling force on a PWC, especially if the wake boarder is engaging in tricks and acrobatic moves, as is currently popular. As understood by those of ordinary skill in watercraft design, towed objects that are moving different directions, especially at high speeds, can have a significant impact on the yaw, roll, and pitch of a vehicle.
Another issue associated with towed objects is the structure used to support the tow rope. In an effort to lift the rope above the surface of the water, upright pylons are commonly used. To adjust the height of the tow rope above the water, telescoping pylons are used. Telescoping pylons are convenient because they retract when not in use. However, the telescoping feature can be problematic due to interference between the telescoping elements, which can cause jamming and affect operation. Also, rust and salt corrosion are common problems in marine environments that can affect the performance of moving parts.